Scattering From a Large Planar Slotted Waveguide Array Antenna

Abstract

ABSTRACT The problem of scattering from a large planar slotted waveguide array antenna is investigated. The structural scattering and slot scattering are solved independently through the application of the equivalence principle. The former is calculated by a high-frequency method, such as the physical optics (PO) and the shooting and bouncing ray (SBR) method combined with edge diffraction. The latter is solved using the method of moments (MoM) in conjunction with global sinusoidal basis functions and Galerkin's testing technique. Special attention is paid to the evaluation of the admittance matrix elements, which involve the internal and external mutual coupling. Numerical results are presented to demonstrate the effects of a variety of factors on the radar cross section (RCS) of a slot array, and these include the number of basis functions in the MoM solution, the external mutual coupling between the slots, the waveguide terminations, and the host object. Also given are the RCS space distribution and the time responses of slot arrays to illustrate their unique scattering characteristics. The RCS of a complicated real slot array is given finally to demonstrate the capability of the numerical method as well as the distinct features of its RCS pattern.